Keeping the vegetable garden full in spring and summer shouldn't be a problem, but it is easy to lose sight of the next season. This is the time to take action, as rich pickings will not last for ever.

First, clean up

Dan turning over the soil. Photograph: Howard Sooley

It is important to keep your kitchen garden clean to avoid the build-up of pests and diseases. Stay on top of weeds and cut the mildewed tops on the beans once they are over. The roots of all the legumes, which are nitrogen-fixing, should be turned back in, where they will leave their goodness to the next crop. Sow green manure rather than leave the ground bare over the coming months. Vegetables are hungry and need good ground if they are to do well, so keep up the soil fertility.

Prepare the soil

A packet of green manure seed is much easier to apply than old-fashioned muck, and will be ready to turn back into the ground within eight weeks if the weather's on our side. Alternatively, a winter-hardy crop such as Hungarian rye grass can be left in the ground until March. It will protect your soil from the elements and keep it weed-free whilst it is fallow. Green manure crops are usually broadcast and raked into the ground, where they will germinate evenly as a continuous blanket of vegetation. Cover the newly sown ground with fleece to keep it moist and warm to aid germination.

Rhubarb

Where there’s muck ... Rhubarb is not a fruit but a hardy winter vegetable - and it thrives in manure. Photograph: Howard Sooley

As autumn fades and winter begins, you can start to plant up the hardy winter vegetables, such as rhubarb. The best rhubarb crops are drawn from those that are split and divided every fifth or seventh year. Autumn is the ideal time to cut away a good wedge, taking a couple of "eyes" and some fleshy root from the clump. The best material is always to the outside, and the old crown can be discarded. Move the plants to a new position where the ground might not be depleted by the parent plant, manure it well and don't crop for the first year.

Garlic

Garlic can be sown until November. Photograph: Howard Sooley

Garlic should be planted in October and November, the bulb broken into its respective cloves and set in rows in the warmest part of the garden. It is worth buying certified virus-free stock. It always amazes me how rapidly they spear the ground when the weather is drawing in, but despite the winter they will stand up to the cold. Free-draining ground is important, and as they will need to stay where they are until the foliage yellows at the start of next summer, you will have to plan around them with other winter works. Onion sets or young plants sown earlier in the summer can be planted out in a warm position too.

What to sow now

While there is still time left in August, sow onion seed for cropping in the summer next year. Sow in directly in well-prepared ground. Put three to four seeds at 6in intervals in the drill and thin later in September back to the strongest individuals. Onions are winter hardy as long as the ground is free draining.

Sweet peas are best sown in autumn and overwintered in pots in a cold frame. Photograph: Howard Sooley

There are several crops that benefit from a winter in the ground, or at least the chill of winter to get them off to a good start next year. Sweet peas are always better from an autumn sowing and for being kept in pots in a frame, rather than started off in the spring. The energy they put into their roots makes a profound difference in getting them out of the blocks as soon as the weather warms, and I will be planting mine out in March into ground that was manured over the winter.

The same goes for broad beans, which are sown at the end of October, but they should be sown direct in the ground and will overwinter quite happily, as long as they are established before the worst of the cold weather descends. Autumn-sown broad beans will be less prone to blackfly the following year and they will crop earlier than those sown in spring. If you are gardening in an exposed position, choose the shorter-growing varieties to escape the winter gales, and be sure to keep an eye on slug damage when the weather is mild.

Brassicas

Plant chicory now and you’ll harvest it through to Christmas. Photograph: Howard Sooley

With warmth in the ground and the promise of moisture ahead, these are perfect growing conditions for establishing plants before the winter. The brassicas are the most pressing job, if you haven't got them in the ground already. It is too late to sow seed if you want more than leafy Russian kale (purple sprouting, sprouts and cabbages are best sown in a nursery bed in June and then transplanted in July), but it is still possible to buy plug plants to take advantage of the remainder of the growing season. You'll need room, with a couple of feet between the rows and at least a foot between plants. I always plant closer and thin down to the ideal spacing. The thinnings, or at least the most succulent young foliage, can go in the pot as greens. Leeks and chicory should also be in the ground by now, but if the plug plants come to nothing, you can easily eat them while they are young. A handful of blood, fish and bone per square metre helps to give the plants energy, and is worth adding to the soil when planting.

Potatoes

If you haven't dug the last of your potatoes already, do it while the soil is still relatively dry, because as soon as the weather gets damp again the ground slugs will be at them. Store them somewhere cool and dry in paper sacks to prevent them from going green, and don't be tempted to store your own for "seed" potatoes. As with garlic, it's best to get new stock that has been certified disease- and virus-free.

Mediterranean veg

Artichoke. Photograph: Howard Sooley

Cardoons and globe artichokes are Mediterranean vegetables which prefer a warm position and a good start before battling a wet British winter. If you are starting from scratch, prepare the ground this side of winter and plant at the back end as the weather warms to spring. The same applies to asparagus, but you will need to find a permanent position for an asparagus bed, as they need at least two years to settle in before cropping, and shouldn't need to be replanted for at least 15 years.

Preventing predators

I net my brassicas to keep the pigeons off the rows, as they will tear them to tatters in no time; but I also do it to keep the cabbage white butterflies off the crop. A fine net - or, better still, fleece - will keep them from laying eggs on the foliage and save you from having to pick off the caterpillars. The bright green caterpillars will strip your plants if they go unnoticed, but they are easily removed by hand - if, like me, you garden organically. I throw them over the chain-link fence in the hope that they will find something to eat in the undergrowth there.

Rotate your crops

I have already planted my brassicas on the allotment in the ground that was previously put down to the potatoes. Strictly speaking, you should follow a three-year rotation cycle, never growing legumes or brassicas or root crops in the same place within the cycle, although this isn't always practical if you have limited space. Much the best reason for rotation is that certain crops demand certain minerals from the soil, and over time they will deplete these essential components if they are repeatedly planted in the same place.

Leafy greens

Brilliant rainbow chard. Photograph: Howard Sooley

The warmth in the ground means that there is still time to sow rows of leafy vegetables. Leaf beet or chard is remarkably hardy and can be cropped up until December and then again after February, as the weather begins to warm up again. In the dark months of winter you need to leave them with some growth on them if you are expecting to be able to crop again in the second half of the winter. The foliage can be eaten like spinach and the fleshy mid-rib is delicious braised with olive oil, lemon and a clove of garlic.

Saving seed

I saved seed from the mustard greens this year. They were at their best and most delicious in the heatwave that struck back in June, and I was picking their foliage then for its peppery kick, but as they ran to seed in the heat I started adding the flower heads to the salads because they were just as delicious and a pretty addition. The long and short of it was that the mustard patch was never re-sown to keep the rotation going, but the upshot is seed that I can save for another year. The swollen pods are collected just before they burst and put upside down in paper bags to dry in the garage. When I clean them, separating seed from chaff, a pinch will be put back in the ground in the hope that we will have an Indian summer. They will keep us going in leaves until my interest shifts towards the winter vegetables.

Keep warm this winter

Broccoli. Photograph: Howard Sooley

If you have a polytunnel or a glasshouse, you can crop the brassicas, leafy veg (such as beet) and several salad crops throughout the winter months. Polytunnels are great walk-in spaces that allow you to garden throughout the winter and extend the growing season quite considerably. If space is an issue, you can keep your winter garden growing on a smaller scale with cloches. The mustards, chicories, mizuna and several varieties of lettuce are hardy, given a little shelter and a bright position, and I will be sowing this month in the hope that we'll be in for a mild winter, and that I'll be able to eat my greens throughout.

Winter is a busy time. You can dig in the muck when you need to keep warm so that ground is settled again by the spring, and turn the compost into the trenches for next year's climbing beans. You will be spraying the peaches against leaf curl after leaf fall and starting the winter pruning of the fruit trees. I like to get any bare-root fruit in before Christmas, though you will be fine to keep planting until the end of March, whenever the weather is mild enough.

If you have managed your ground with foresight, there will be the added incentive of being able to return home at night with produce to keep you out of the supermarket, and happy in the knowledge that you are working your ground hard - and that it's returning the favour.